title: [Study of spectral and luminescent manifestations of the aggregation of thymine chromophores in aqueous solutions of polythymidylic acid at room temperature in connection with the task of photochemical record of information on thymine].
abstract: Luminescence and excitation luminescence spectra of water solutions of polythymidylic acid at room temperature were studied. Three luminescence bands at different excitation wavelengths were observed: at 338 nm, which was known earlier, and two new bands, at 320 and 350 nm. The study of excitation luminescence spectra that have not been studied earlier led us to interpret the band at 320 nm as a band of chromophores that do not interact, the band at 338 nm as a band of photochemically most active densely packed stacking dimers (absorption band exciton splitting approximately 4000 cm(-1)), and the band at 350 nm as a band of photochemically inactive big stacking aggregates (n > or = 10, exciton splitting approximately 8000 cm(-1)). Changes in optical density at 270 nm of poly-T water solutions after consecutive irradiations with UV light at 297+302 and 248 nm were studied. The causes of incomplete reversibility are discussed.
authors.forename: V M
authors.initials: VM
authors.lastname: Malkin
authors.forename: V L
authors.initials: VL
authors.lastname: Rapoport
mesh_terms: D008163:Luminescent Measurements / Q000379:methods; D010777:Photochemistry / Q000379:methods; D011071:Poly T / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods; D013941:Thymine / Q000737:chemistry*
chemical_list: D011071:Poly T; D013941:Thymine